The present invention relates to a bearing ball spacing retainer made of thermoplastic material and enabling the manufacture of ball bearings having a large number of balls on which correct guiding action is exerted.
Spacing retainers of the aforementioned type usually comprise a ring and a number of pairs of deformable tabs projecting from the said ring in the retainer axis direction. On each pair of tabs adjacent with each ball, a ball seat is formed comprising a spherical surface portion. Each of the said tabs projects axially beyond the ball centre plane, in such a manner as to form a back draft for the ball with which it is in contact, and so prevent the ball from being withdrawn from its seat.
Though on the whole fairly satisfactory, a major drawback on retainers of the aforementioned type is that they are poorly suited for use on bearings having a large number of balls and, consequently, little clearance between adjacent ball surfaces. In fact, the gap formed between two adjacent balls is too small for accommodating, as it should, two retainer tabs, without the thickness of the latter, particularly the radially innermost part, being excessively reduced.
Consequently, retainers of the aforementioned type cannot be employed on bearings having a large number of balls or, more generally speaking, when the said balls are packed closely together.